Engine Modes

Ratio range: 2:1 to 8:1 (PRESSURE driven)

Attack: 0.1-100 ms (clamped). Scales from 30 ms at P=0 to 1 ms at P=1.0.

Release: 10-2000 ms (clamped). From 1200 ms at P=0 to 100 ms at P=1.0.

Knee: Scales inversely with ratio - wide (12 dB) at low PRESSURE, narrow (3 dB) at high. The result is gentle control at low settings and firmer shaping as you lean on it.

Sidechain HPF: Controlled by TONE. tone² × 60 Hz, range 20-120 Hz (reduced from 150/300 in v1.2 to keep bass in detection per Pro-C 2 Bus defaults).

Ratio steps: 4:1 (P<60%), 8:1 (P<80%), 12:1 (P<92%), 20:1 (P<97%), All Buttons In / 21:1 (P≥97%)

Attack: 20-800 μs (microseconds, not milliseconds). This is the fastest attack envelope in Pressure.

Release: 50-1100 ms. Follows a V-shaped curve: shortest at P=0 and P=1.0, longest at P=0.5. Formula: 50 + 400 × P × (1-P) ms.

Input drive: Threshold maps to inverted input gain so higher PRESSURE pushes more level into the detector. More drive means more compression and more attitude.

Saturation: Two-stage FET saturation adds harmonic content. Output gain automatically compensates for input drive and saturation gain.

Sidechain HPF: None. The FET engine does not use sidechain filtering.

Ratio: Continuously variable from 2:1 to 12:1. Not stepped - the detector's sensitivity creates an emergent ratio that varies with signal level.

Peak Reduction: Maps from PRESSURE via threshold. At P=0.5, peak reduction is ~30 (moderate); at P=1.0, it reaches 60 (heavy).

Attack/Release: Hardwired in the optical cell model - not user-adjustable. The optical element has inherently smooth, program-dependent timing.

Tube warmth: Subtle, musical even-harmonic warmth from the tube stages, deepening as compression increases. The DRIVE knob adds more of this tube colour as you push it, while the optical gain reduction itself stays clean.

TONE behavior: Controls emphasis (not sidechain HPF). Maps directly to the optical cell's emphasis parameter.

Ratio range: 2:1 to 8:1

Attack: 3-30 ms. Slightly slower than VCA to preserve drum transients.

Release: 100-300 ms. Auto-release tuning set separately for program-dependent recovery.

Knee: Always hard (0 dB). No soft-knee option.

Sidechain HPF: Controlled by TONE. tone² × 120 Hz, range 20-120 Hz. Protects kick drum from triggering excessive compression.

Ratio range: 2:1 to 8:1. Variable-mu ratio modulation in the engine makes effective ratio change with signal level.

Attack: Clamped 0.2-30 ms. Lower PRESSURE stays quicker; higher PRESSURE expands into slower mastering-style timing.

Release: 300-5000 ms. This is the longest release range in Pressure and is tuned for broad, low-drama control.

Knee: Always wide (10-24 dB, enforced minimum 10 dB).

Tube warmth: Even-harmonic warmth that adds perceived loudness and body without raising the actual level; the TONE knob shapes how much.

Sidechain HPF: Controlled by TONE. tone² × 80 Hz, range 20-160 Hz (reduced from 120/250 in v1.2 to keep the detector more mid-inclusive).